Physical Sciences and Mathematics Commons^™

Random first-order transition theory is used to determine the role of attractive and repulsive interactions in the dynamics of supercooled liquids. Self-consistent phonon theory, an approximate mean field treatment consistent with random first-order transition theory, is used to treat individual glassy configurations, whereas the liquid phase is treated using common liquid-state approximations. Free energies are calculated using liquid-state perturbation theory. The transition temperature,, the temperature where the onset of activated behavior is predicted by mean field theory; the lower crossover temperature,, where barrierless motions actually occur through fractal or stringy motions (corresponding to the phenomenological mode coupling transition temperature); and, …

Calculations of the energetics of formation, stability, and reactivity of o-semiquinone, p-semiquinone, and phenoxyl radicals have been performed using B3LYP/6-31G(d,p), BHandHLYP/6-31G(d,p), BHandHLYP/6-311++G(d,p), BHandHLYP/aug-cc-pVDZ, and QCISD(T)/6-31G(d,p)//BHandHLYP/6-31G(d,p) model chemistries. Formation of these radicals from potential molecular precursors catechol, hydroquinone, and phenol is readily achieved under combustion conditions through unimolecular scission of the phenoxyl–hydrogen bond or abstraction of the phenoxyl hydrogen by a hydrogen atom or hydroxyl radical. The resulting radicals are resonance stabilized and resist decomposition and oxidation. Activation energies for the decomposition of the radicals through concerted elimination of carbon monoxide range from ≈55 to 75 kcal/mol. Activation energies for the …